Fuel Pump
Upgrade the Fuel Pump
At the very minimum, a 255lph fuel pump is required, Walbro makes a nice unit that sells for half the price of a new OEM pump cost. Installation of replacing the fuel pump process is quite straight forward and well documented on forums and Youtube.
There is a common problem among these vehicles of the connector plug for the fuel pump and sending unit shorting out inside due to corrosion. Its recommended to remove this connector and solder the wiring direct connect to eliminate future problems.
Walbro High Pressure 255LPH Fuel Pump
Fuel pump & install Kit – PN# GSS341/GSS341/GSS340 Install Kit – 400-739.
Supports up to 500 Horse Power.
Fuel Pressure Regulator
Optional Adjustable Fuel Pressure Regulator (AFPR)
This isnt required but can be handy to dial in your injectors or increase pressure to reduce duty cycle. An adjustable fuel pressure regulator will allow you to raise the base fuel pressure reducing the duty cycle of the injectors- ultimately allowing for higher boost with out maxing out the injectors. Its recommended not to raise the base pressure 20% over stock pressure to limit stress on the fuel pump. Should your setup require more then a 20% increase, larger injectors would be required.
The standard AFPR that you will need is anthing for EFI rated that is adjustable from 0-100psi. Many regulators are adjustable from 30-70psi and this will work just fine.
The Stock Fuel Pressure for a KL V6 Engine is 44psi.
Fuel rail adapter
Should you add an aftermarket fuel pressure regulator, you may need a fuel rail adapter, these are becoming increasingly more uncommon to find, and the next viable option is using a 1/4NPT Tap to thread the outlet for the stock fuel pressure regulator on the fuel rail.
Dual Feed Fuel System
This isnt required, but it a nice upgrade if your planning some big power. The stock setup is a series setup, the injectors are fed from the rear bank to the front bank and returned to the tank. In theory, the front bank injectors could lean out in a high output situation as the rear bank is pulling fuel first. However, this may just be theory, as the regulator sets a consistent fuel pressure that pressurizes both rails at all times.
The dual feed setup will send divert the fuel equally between the fuel rails, thus eliminating a risk of fuel starving on the front bank.
Below is a diagram of how this is setup along with part numbers to popular fittings needed.
The below picture links to our How To Guide that illustrates the plumbing for single and dual feed setups, along with a list of the required parts to build your AFPR setup.
